Posted tagged ‘forcible entry’

Editor Note: The mechanical advantage of a Halligan has been a recent topic on some training forums. A friend of mine decided to sit down and put on paper what many of us explain when teaching the use of the Halligan. Before you read this I would like to start by saying this is an article for firefighters that like to keep working towards a better understanding of what they are doing and why they are doing it. Does a firefighter need to know the complete break down of mathematics regarding the leverage of the Halligan to force a door correctly? No, not at all. But a firefighter that is instructing others on how to use this tool should have a very solid grasp of how to use the different fulcrums of the tool and should be able to explain where you have more or less leverage depending on how you use it. This article allows you to take a detailed look at what the numbers can look like. This is for those of you that pay attention to the details but still understand the practical application of how this translates to actually using the tool. Understanding leverage and fulcrums is a big part of our job, during the overhaul portion of a fire ground it is very easy to see who has good understanding of tools and their leverage points, hopefully this helps bring a little further understanding to this topic.

Halligan By The NumbersBy Ben Shultz

Let me start off saying that I do not hold a degree in applied mathematics, trigonometry or physics. I do however like putting numbers and statistics to things that I do. It’s simply what works for me and helps to solidify concepts in my mind. So, with that said, here is a short document about the mechanical advantage that we create with the halligan. There are some folks out there that would tell me how I forgot to factor in Pi, a cosign, theta, etc. and therefore my math isn’t perfect. They’d be correct. But, when we keep things simple and look at the halligan as either a class I or II lever, we can still come up with some decent numbers to show the force it can create in different applications.

Quick overview of levers…they are a simple machine. They fall into three classes – I, II, or III. In the case of the halligan, it operates in the class I and II mode. Below you will see an example of a class I lever and how mechanical advantage (MA) is calculated. Example: a seesaw.

So, you can see in either mode, we need to know the distance from the force (the firefighter) to the fulcrum, and we need to know the distance from the load (the door) to the fulcrum. These numbers allow us to arrive at our MA.

So, here’s what we know about the halligan before we even apply it to a door…

The halligan is 30” in overall length.

The forks are 6” and the crotch is 5”.

The adze is 6” in length.

The adze is 2” wide.

The pick is 6” in length.

The adze/ pick triangle is 5” tall.

With those numbers in mind we have most of what we need to determine how much MA we create in different positions on the door, as you will see below.

Outward Swing Doors (Towards you)

It is often advantageous to gap, crush, tunnel, etc. an outward swinging door to assist in setting the adze. By placing the halligan in such a fashion (disregard hand position and how low on the door the halligan is placed) and moving the bar up and down we are using 30” of the bar from the fulcrum and the door is being impacted by the edge of the adze, which is 2” from the fulcrum. Therefore, we create a 15:1 MA (a lot of force!)

Once the door is gapped, we can either drive the adze in and set it or we can drive the forks in. I’ve heard numerous arguments for and against both methods, and that is a whole topic in itself, so for now I’ll just stick with the MA examples of each.

(Door removed for picture purposes)

In this fashion, we see the adze driven to its “mark” that lets us know we’ve driven far enough to clear the jamb and catch the door effectively. This puts 4” of adze past the outside edge of the door frame. That frame edge is our fulcrum. You’ll notice that where the jamb or rabbit is located is at the 2” mark, representing where the inside door edge would be located (the load). This equals 2” of distance from the load to the fulcrum. Once again the distance from the force to the fulcrum is 30”, giving us a 15:1 MA.

Here we have placed the forks for the outward swinging door. Once again, there could be a entire discussion devoted to bevel away or towards a door in forcible entry, but we’re just sticking to MA for now. Note that the fulcrum (outside edge of door frame) is created at about the 3.5” mark. The jamb is located at the 1.5” mark. Once again our load to fulcrum distance is 2”. However, in the forks configuration, we lose a bit of MA, because our force to fulcrum distance is reduced by the length of fork we drive past the fulcrum, in this case that is 3.5”. Therefore we end up with 30” bar minus 3.5” for a force to fulcrum length of 26.5”. So our MA is 26.5 / 2, which equals 13.25:1, still significant, but reduced from the adze application. What’s important to note is that if we had driven the forks to the crotch mark, as is often taught, we reduce our MA to 25/2, or 12.5:1. I know the concept of driving the forks to the crotch is to assure that you have cleared the jamb and have enough fork to grab the door, but it is obvious from this picture that those concerns are addressed with a shallower drive. It’s something to think about.

Inward Swinging Doors (Away from you)

Here we see the set up to initially gap (and possibly force) the inward swinging door. The halligan is used in the same fashion as gapping the outward swinging door, just in a different position. By pushing down on the bar and forks we create a fulcrum on the edge of the 2” wide adze, therefore, the math doesn’t change and we have a 15:1 MA. It’s important to realize that pulling up in this configuration (right side opening door) greatly decreases your MA due to the length of the pick.

Up until now, the halligan has been used in the class I lever mode. Here we find it used in the class II mode. In this set up, we have driven the forks to the crotch mark. This creates our fulcrum at the edge of the door frame at the 3” mark and puts our load at the jamb at the 5” mark, once again, giving us a load to fulcrum length of 2”. Because we have driven our forks 3” past our door frame edge (fulcrum), we have also reduced our force to fulcrum length by 3”, resulting in a D(f) of 27”. Therefore our MA is 27 / 2, or 13.5:1. Once again, I know it is often taught to drive to the crotch, but remember, the deeper we drive the forks, the less MA we have available to us.

I’m sure with the 90 degree bend in a halligan bar and the curve of the forks that there are some really fancy equations to truly figure out the exact MAs for the halligan. So, if you’re not entirely thrilled with the numbers as fact, consider them arbitrary values and simply think of the different configurations as “more” or “less” MA. The key is to have a good grasp on the capabilities of the tool. And don’t forget, in order to achieve the greatest mechanical advantage you have to maximize the force to fulcrum distance, meaning you must pull or push at the end of the halligan. The closer you move to the door, the less MA you realize. With that said, remember that you can increase your force to fulcrum distance, therefore increasing your MA, by introducing a roof hook into the mix or marrying up another halligan at the forks. Finally, like most things in life, there is a trade-off involved. The greater your MA, the shorter your “throw” when forcing a door and vice versa.

(Editor Conclusion)

I first saw this “ballpark mechanical advantage explanation” from Josh Materi while he was explaining Halligan use in a hands on forcible entry drill (video below). Josh does a good job explaining a couple of other ways we commonly use the tool that is not included in the numbers above. What you have to keep in mind is as you force a door and material starts moving, fulcrums change and so does the point of the tool that is prying on the door. This is what makes this rough math and a constantly changing mechanical advantage but you get the picture. Josh breaks down the adze end of the tool into three major categories (the 2″ adze, the 6″ adze and the pike/adze combo) This is the easiest way I have found to keep it simple when instructing which part means what when we put it to work on a door. Thanks a ton to Ben Shultz for writing this article and Josh Materi for permission to use his video clip. -Royal

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A quick thought on kicking doors. We teach not to do it. Not because it won’t open doors, because honestly it will open a lot of them. I am not trying to kid anyone and say that we have not kicked open residential doors before. But I will say when I was still kicking doors open it is because I didn’t properly understand how to use a Halligan bar. So kicking was the easiest way for me to open an apartment door that was on fire. After I gained some experience, learned my way around a set of Irons and really thought about when and when not to kick a door, it became real clear to me that because I was now properly trained on a Halligan bar (and I carry it), there was no reason for me to kick doors open. They can be opened just as fast with a competent person on the tool. The other thing I noticed was kicking doors was wasted experience, it was a perfect opportunity to hone your skills with the Irons on a real door in a real frame. Thus building your confidence and not letting all of your experience be based on a forcible entry prop. Lastly, when luck runs out, because at some point it will, a person who is competent on their Irons now has multiple options and is very proficient in them because they have been forcing doors with the Irons for most of their career instead of kicking them for 15 years. Attacking doors based on knowledge rather then luck will give you a much stronger foundation when it’s time to force the doors that are out of the ordinary. You will find doors you cannot kick, and when you do, and the luck of kicking runs out, you will set the tone for the fire ground with a real bad forcible entry situation. To many people are relying on us to base our operations on luck. Long live skillful Irons work!

These doors are all out of occupied residential homes.

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Commercial outward swinging doors can be some of the most difficult forcible entry situations due to the locking systems and added fortification but what is often overlooked in training is access challenges.

This outward swinging door on the back of a commercial building has a half wall on the hinge side and the jamb side is recessed in the masonry block. While few would consider the “confined space FE” it still limits our working area. The half wall may prevent the use of a married hook here and the recessed jamb limits the prying ability of our adze.

You can see that the Halligan is going to max out before we even use half of our full prying range of this bar, this could easily prevent us from getting enough leverage to force the door.

The upside to this situation is that end of row bricks and block are very weak points and can be blown out easily with a strike to the corner with the flat head creating ample room for a full force.

You can now return to your Halligan and properly set the tool all the way behind the door. When you pry outwards you will have the full range of motion and gain the maximum amount of pry and throw from your Halligan.

This can be difficult to fully explain and see the advantage of this tactic in photos. Below is a quick video showing how effective crushing the block can be.

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Here is 15 minutes of padlock forcible entry done by the Irons, Saws, The PIG, Bolt cutters, etc. Dozens of locks later, we have a short forcible entry training video. This gives you an idea of what locks can easily be defeated by the Irons, which ones may need saw work, and when bolt cutters can actually beat both of them. We still show a majority of Irons work because you should be carrying them and they always start. However the saw does have great application when it comes to padlocks.

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Here is a short clip of my modified Rex Tool being used to go through the lock on a storefront door with a mortise cylinder. I have been carrying this modified Rex for almost 5 years now and have to say it is probably the most versatile through the lock tool you can have. I don’t carry it all the time but it goes in my pocket for fires, service calls, investigations, etc. Through the lock is a great Plan A on a good majority of Aluminum Stile Doors with Mortise Cylinders. However, it will never happen if you’re not carrying your Rex, this helps you in that complication.

Another throwback article. Here is a collection of all the door size up articles we have posted over the years. Each of these work great to sit down with a couple of guys on the computer and practice your size up. You can scroll down and see the outside of the door, give it your best shot, and then scroll down to see the interior and the following write up. If you can go through these without much difficulty it shows that you are pretty dialed in when it comes to understanding doors and locking systems. Door size up matters, its what bases your forcible entry operation off of knowledge instead of luck. Any questions, comment on this article and we will get back to you.

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Need a new years resolution. Here it is, prove to yourself and others how effective Thru-The-Lock is on storefront doors. It is hard to argue with this video. Time to quit ignoring that Rex or K-tool everyday as you check the trucks and start dedicating yourself to completely understanding it uses.